They first year of an infant’s life which is before they can utter their first word are known as prelinguistic stage. Children do not utter their first word until they are about one year old. At one month, they show categorical perception of speech. A perceptual ability is ability to segment one sentence into individual word units. This ability usually leads to production and thus helps in the development of speech production.
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Even though children do not produce their first word until they approximately 12 month years old, the ability to produce speech sound start to develop at a much younger age. After the mother giving birth, the young infant will produce undifferentiated birth cry. Within 0 to 6 weeks, the infant can produce reflexive sound which are glottal catch and vowels such as ah, eh, and uh. Plus the infant also can produce some variety non-crying sound. They also produce differentiated cry which that true vocal communication begins. In the range 6 to 16 weeks, infant start to produce cooing sound when they are happy. Moreover, they begin to produce single syllables and blowing bubbles.
At 4 month, infant still prefer infant-directed compare to adult-director speech. Plus by 4 month, infant have learned which feature they have to pay attention to at the suprasegmental level such as intonation and stress. At 5 months old, infant prefer to hear their own name to similar sounding word. On the other hand, by 6 month old, they expose more to their native language and start to learn not to pay attention to sound that are not meaningful in their native language.
The production of vowel sound in the first 2 month lead to the production of consonants. First back consonants ([g], [k]) are being produce around 2 to 3 months and front consonants ([m], [n], [p]) is being able to produce by infant at about 6 months old. In the range 3 to 6 month, babbling begins influence by their native language. In addition, they babbling show pitch and inflection change. They start to produce double syllables-VCV such as aga. Children are also able to puts lips together and say “m” and nasal tone is heard. Not only that, they also begin to vocalize their pleasure and displeasure. Infants in this range will stop vocalizing when adults enters and have self-initiated vocal play. They are also cooing, chuckling, gurgling and laughing.
At 7 months, they able to segment word from speech that shows a strong-weak stress pattern, which is the most common stress pattern in the English language. The process that allows infant to use prosodic cues in speech input to learn about language structure is known as ‘prosodic bootstrapping’ . While children at 8 months old generally do not understand the meaning of the most single word yet, they still able to understand the meaning of certain phrases they hear a lot. By 9 months old, infant can differentiate native from nonnative language. Children uses [m], [n],[t],[d],[b],[p] and [y] in babbling multiple syllables by 6 to 9 months old. They babbling tunefully or singing tones and uses several of sound combination. They also begin to have inflected vocal play and intonation patterns heard. Infant also copy intonation and speech sound from the adult in their own repertoire. Reduplicative babbling begins for example bababa.
From 9 to 12 months, children vocalize during play and also begin to vocalize in front of mirror. They are able to jabber loudly with wide variety of sounds and intonations. Infant combine different vowel and consonant into syllable string in vocal play and at this stage phonetic drift begins. Infant also acquire variegated babbling and combines different syllables in vocal play. At this stage, children normally have not yet begun to speak and thus have no production vocabulary but in the range 10 to 11 months old, children’s comprehension vocabulary size is about 11 to 154 words . During this transitional period from babbling to the utterance of the first word, children also produce “protowords”. Protowords is invented words that are used consistently to express specific meanings.
In the range 1 year old to 1 ½ years old, infants usually use jargon to communicate. We can also hear some repetition of words or echolalia. They are uses most vowels and consonants and some initial consonant. Basically, their utterances unintelligible with exception of a few words. Intelligibility refers to the proportion of the speaker’s output that listeners can easily understand. They commonly leave out final consonant and some initial consonant. By the range of this age, they start to produce word in VC structure such as bo/boat and able to imitates some word accurately. By 14 months old, children usually produce their first word. First word is simple structure and contains the same sounds that were use in late babbling. At 16 months children comprehension vocabulary size ranges from about 92 to 321 words. At this age, children’s production vocabulary size at this age is typically around 50 words. Children’s production becomes more consistent around the age of 18 months.
Within 1 ½ to 2 years old, children’s words increasing in frequency and jargon almost gone by 2 years old. Commonly, they will ask questions by raising intonation at end of phrase. Plus, children show improvement in intelligibility. Approximately 65% intelligible by 2 years. In addition, word produced with CVC structure such as big appear at this range of age.
Intelligibility improve when they at 2 to 2 ½ years old from 65% to 70%. Plus, they may skip over final consonant, reduce consonant blend and substitute one consonant for another. The size of the vocabulary production is about 50 to 550 words. Children also seem to build up their vocabulary faster if the speech they hear is related to their focus of attention more often.
At 2 ½ to 3 years old, children still do some substitution and alteration of consonants. They continue to improve their intelligibility to approximately 80%. By this age they can mastered consonants; [p], [m], [n], [w], [h].
Children at 3 to 3 ½ years use final consonants most of time. At this age, Final-Consonant Deletion process, consonant assimilation, diminutization, doubling, prevocalic voicing, reduplication unstressed syllable deletion and velar fronting should be gone. Children become very intelligible in connected speech by age 3 ½ years to 4 years old. They had mastered consonants;[b], [d], [j], [g], [f], [y]. Plus, phonological process continues which are cluster reduction, deplatalization, epenthesis, final devoicing, gliding, stopping and vocalization. In 4 to 4 ½ years, should be few error and substitutions of consonant in children utterances. They become more intelligible especially in connected speech. At the range 4 ½ years to 5 years old, children use most consonant sounds consistently and accurately. Even though, more errors present in difficult blends. At 5 to 6 years old, children mastered consonants such as t, ing, r, l. Follow by 6 to 7 years old, they begin to mastered consonant such as voiceless th, sh, ch, j.
Hence, young children have remarkable ability to learn meanings for the words they extract from the speech they are exposed to. Acquisition of the language is strongly relate with environment. The phonological development should be know by parents to detect any phonological disorder on their child.
